Nemesism
by bluewindfall
Summary: Some warnings first: manga spoilers, major character death, implied suicide. AU: For a while he could pretend, but all things come to light with time. And...as he was told, the new world will be hell; Yukio thinks it won't be much different, but he fears he'll fit in better. Also on AO3, but different summary because this box is too small, not enough words T.T Sequel to Temporize


Sorry, it doesn't start yet, here's some notes first:

Okay! Before you read beyond this point, I just need to say again, this has some vague spoilers from the manga up to chapter 111, so if you haven't read that far, and you don't want spoilers, don't read this. :) If you don't care, then feel free to keep going! Also, this is the sequel to another fic I wrote called Temporize. You don't have to have read it to understand this, and you can go read it after if you like; the sequence doesn't really matter.

Also, I used a bunch of quotes from the manga again, so here's this list of where they came from in case you are curious and would like to know:  
1\. "Everyone carries a burden but also cares for others." Yukio thinks this to himself in chapter 80, and a little later, he adds on that he needs a broader vision. This was very interesting to me and I'm super excited to see if it'll come up again! :)  
2\. "Which side are you on?" This comes from chapter 110, where Yukio asks Shima this first, then Shima turns it around and asks Yukio the same thing.  
3\. "From...from now on...he would protect Nii-san in Tou-san's place." Yukio says this in chapter 2 to Mephisto as, "From...from now on...I will protect my brother in my father's stead," or at least it's translated this way, so yeah I just changed it slightly to fit the POV and narrative I'm using, plus throwing in the Japanese terms of address...just because I like it better.  
4\. "Yukio, rather than living in fear of the darkness, become strong for other people, including your brother." Okay, honestly, I think this line has showed up more than twice, but for now I've only found it in chapter 2 and Yukio recalls it in chapter 69, where he adds on that he wants to become stronger than Rin now. It's from a flashback where Shiro says it to little kid Yukio.  
5\. "But if she knew the real me...she would despise me." Yukio says this to Rin in chapter 80 when they're talking about Shiemi.  
6\. "You said something, didn't you? If Tou-san could ever be said to have had any weakness, it would have been you. You...Nii-san, were the one who killed Tou-san." This is a condensed version of what Yukio says to Rin in chapter 2. Just such a heartwrenching scene, for both of them really. I really liked this part. It introduced Yukio's character so well. ^^  
7\. "Just die, please." This is from the same part, just a little earlier in chapter 2. Yukio says this to Rin.  
8\. "In ten years time...your brother will witness something far more frightening. Rather than living in fear of the darkness…" This is the really cryptic line that Shiro says to Yukio in chapter 2. Honestly, there are so many good lines in chapter 2. XD  
9\. "To become strong, and be able to protect other people-your brother included." This is just the same line from chapter 2, but also from 69. I just added it again, but with an em dash instead of comma because I thought, IDK, maybe it would sound more impactful.

* * *

"I'm supposed to give you this," Shima drawls, handing the mission file over, "we're short-handed and you're the only one who can use the Armumahel-derived weapons long-term. They've been wanting to see you test this out on some high-level demons for a while now."

Yukio frowns, "Why would they choose to abandon this facility before they could recover their research? Why not just move the demons? Unless—"

"You're laying a trap, of course. We've discovered they're involved in deals with the enemy," Shima grimaces, "there's no lenience for traitors."

It doesn't escape his notice that the bomb's design isn't merely targeted to demons. It is a crude device intended for complete lethality.

Just how much blood will he spill this time? How much more until he's—

"I'll let you in on a secret," Shima whispers, "I overheard after the meeting yesterday. They've found a catalyst! They want to test it on the gate in Tokyo. That's why," he nods at the mission file, "they're using it as a weapons testing ground before that. Otherwise, they'd never, you know."

"That means—"

Shima raises a hand, cutting him off as the clattering of footsteps reaches their narrow hallway, gesturing to his mission file wildly. Yukio resists the urge to roll his eyes. It's nothing he's not used to by now. He's had too long to practice and refine his experience in deceit; he may not have Shima's finesse, but he is at least competent.

"This seems tactically unsound," Yukio offers as he flips through a few more pages, "How do I know when to set it off?"

"You notify us, and we'll trigger it remotely."

"I understand."

They stand there, eyes averted vigilantly downward, waiting for the sound of footsteps to fade.

"Relax, the Order is spread thin," Shima grins once they're out of earshot, "you're not going to run into any of _them_." He gives the file two quiet taps as he walks away.

"...It doesn't matter."

"That's true," Shima admits, stopping at the end of the dimly lit hallway. He waves one hand in a lazy salute, "Look alive, sensei! The new world is coming."

* * *

Yukio shuts the door to his assigned quarters behind him quietly, flipping the light on as he throws the mission file onto his desk carelessly.

It's been a year since he left the Order. In the span of only four months, the organization had already begun to fall apart, with Mephisto bedridden, the Paladin resigning and Lightning spreading the truth of the Order's experiments, it is only a matter of time before they will collapse inward.

Now, it seems they won't have the chance. Once the Gehenna Gates open completely, it's likely, with the way things have been going, society will be torn to shreds. Perhaps, the realization that he can't bring himself to care should be more alarming to him. But it isn't.

Rather, it brings with it a sort of calm, an inevitability that renders his current actions obsolete. It's nothing like forgiveness, but it's all he cares for now.

He lingered here, because he'd wanted a place—not like this—but they'd taken him away from the Order...where he couldn't stand to stay.

_Everyone carries a burden but also cares for others_.

He can only ever see himself. The people he once helped, wanting to protect his brother, hoping to become stronger; he has such a vastly empty heart that is so painfully selfish, so focused and egotistical that he can't hate anyone more than he hates himself.

He thinks, if their places were switched, if Rin had been the normal one, Yukio would have noticed how poorly he fit with the others earlier on. That place was so filled with kindness and inspired, genuine people—he could scarcely bear to be their teacher—where he'd thought he was _kind_ too, that he could see beyond himself.

For a while he could pretend, but all things come to light with time.

And...as he was told, the new world will be hell; Yukio thinks it won't be much different, but he fears he'll fit in better.

* * *

He prepares the bomb with ease, infiltrating the facility with fastidious care. The facility is busy, too busy to take notice of him, filled with researchers rushing from room to room and Yukio leaves without difficulty, stripping off the lab coat he'd worn as a disguise as he strides straight out the doors.

Once he arrives at his extraction point and contacts headquarters, he's disappointed that they order him to stay and report on the weapon's effectiveness. He waits, oddly impatient, even when he thinks absently that there's nothing he has to do, no better way to spend his time, only prepared to waste away in his room until his next mission.

It's peculiar that he has found himself growing less and less tolerant of the stench of blood when nothing else bothers him anymore.

His hands shake minutely as he raises the binoculars, watching two cars approach, and soon a small team of ten exorcists pile out, heading into the building. He grits his teeth in panic. How did the Order find out? What if they disable the bomb before—

He reaches to report on the situation, but the signal must be weak as he only hears a screech of feedback. _No,_ this was a trap, not for the researchers, but for the Order. Even if he reports back, there's no way they'll agree to stop the mission. Not when this was their goal from the beginning.

Shima lied to him. Yukio has to wonder if it was pity or reluctance on his part. There's a possibility it's a coincidence as well but he can hardly believe that.

He's gone too far now. He couldn't turn back...if he wanted to. He knew this was inevitable the day he left.

It's far too late to try to rectify his mistakes. He'd thought too little of the Illuminati after all; he's been drowning in his own reckless arrogance this past year, foolishly thinking he'd be able to use them to gain what he wanted—the truth about their birth, but so much more importantly, he'd desperately needed power.

That night—when that strange power had appeared in his eye—when Rin's flames had swept down the mountain, Yukio had thought he'd lost control, that this time, the Vatican wouldn't let him go. And the fear had taken root; he was too weak that he couldn't possibly protect Rin if they were to take him away again.

And he'd hated Rin for risking his life to save others using his flames. It'd only made the Grigori more wary of him, while Mephisto vied to use him for his power, as a weapon. He'd hated Rin's heedlessly carefree attitude, as though his own life didn't matter; as though he couldn't be executed at any time, for any reason if the Grigori wished.

He'd tried to suppress Rin, tried to keep him weak—telling him his powers were dangerous, that he couldn't control them—so others wouldn't see his value and manipulate him. Of course, Rin had never listened.

But now, he feels only overwhelmingly apathetic. When the gates open, he doesn't know what he'll do.

He still can't decide if it might be worse that he can't bring himself to feel even vestiges of remorse. He hasn't lost himself, because it doesn't feel wrong; if anything, he must have always been this way.

There was only so much he could do—once the tests revealed he wasn't suitable for demonic possession, he'd lost his value all too quickly—that he could gain without dirtying his hands. So, he'd discarded his gloves, his convictions, submerging up to his elbows in the stagnant, rancid dregs of his own uncertainties and he remembers it was _torturous. _It was then that he discovered how thoughtless he'd been. With no place to return, and nowhere to go, he chose to remain here, shunning the light.

He's not sure why it doesn't hurt anymore but he knows better than to keep his mind on those things.

Still, he doesn't fit in the Illuminati. Loyalty isn't a quality he possesses either.

_Which side are _you_ on? _

But he spots familiar blue eyes—for a minute he doubts his own eyes, _Rin's_ hair wasn't white before—and his heart stops. _Why is he here—he can't be here—what can he do? There's no time left! _

He panics as his communications line buzzes with static, and his stomach twists with fear—if he stays here, if he doesn't do anything...Yukio's seen the power of Armumahel's crystals and flame first hand.

In the span of less than a second, a million thoughts rush through his mind as his panic brews with the sluggish contempt he can't quite grasp anymore.

He's not prepared to cross that line—not _Rin,_ he can't let this happen. Even when he'd pulled the trigger on the bridge, even when he'd had _intent_, he'd never wanted this.

His promise had started out so clear and unhindered. _From...from now on...he would protect Nii-san in Tou-san's place. _

No, he fears even that promise had been tarnished, unclean from within. He has always admired Rin—his confidence, how he didn't need to rely on anyone—and it was that strong desire to be like him that led to his frustration, his _envy_.

No matter how _similar_ they were supposed to be, Yukio has always known the cruel truth, that he could never match Rin's brilliance—not then, of course _not now_.

Rin's strength never came from Satan's powers. His strength comes from that infuriating, repulsively quixotic compassion and wholeheartedness he wasn't even aware of having; that Yukio couldn't comprehend, couldn't stand. Yet, those were the qualities he desperately wanted to mimic, and because he didn't understand, he could never quite manage to be more than a flat imitation.

It's why he left. Rin draws people to him effortlessly, even with the burden of his heritage. But Yukio? He'd known they wouldn't accept him—he'd been trying to dissociate himself from his birth, while simultaneously needing to know an excuse, some motivation, for being allowed to live—hating Rin's powers when he had nothing. Once he'd discovered the taint in his left eye, he couldn't have asked them for help; he wasn't supposed to need help.

He's only ever had _normality_; he's only ever been the plain one next to Rin—they would never accept him like they did his brother. He tells himself it's because he's their teacher that there's a certain distance between him, and the rest of the cram school exorcists. That he needs to maintain a professional relationship, not a close one.

If they have Rin, of course Yukio could never insert himself there. He holds them at arm's length and pushes them away because if they came closer, they'd hate who he really is.

Like Shiemi-san; he should never have gone to her in that state. _But if she knew the real me...she would despise me_. Because _Yuki-chan_ wasn't always fake, yet it was clear, the one time he went to her as Yukio, he'd yelled and pushed her and scared her...it wasn't anything he didn't see coming before.

_Yukio, rather than living in fear of the darkness, become strong for other people, including your brother_.

At first, he hadn't wanted to be a burden. But even that hadn't been enough; he has always been selfish, greedy, and he'd wanted to surpass Rin. Why would he hope for things he could never attain? Why, when he should have known how futile his painful ambition had been?

Why could he not see before...how undeserving Rin had been, of his jealousy?

He can't recall the reason—the fervent need that had plagued him since Shima made his offer—it'd been worthwhile to come to the Illuminati anymore. What use is it, to be immune to Rin's flames, when his true inferiorities stem from uglier, deeper areas?

Does he even want...to save Rin?

Before he knows it, he's sprinting toward the building, gravel scraping the soles of his shoes as his legs move far too slowly, heart throbbing in his chest, bile crawls up his throat as he sees the exorcists head inside.

He needs to make it in time, he _needs to—_

Yukio scrambles to a stop abruptly, watching in horror as the explosion engulfs the entire building, sending a brilliant column of black flame striving for the ashen sky. Hot air berates his face as he's nearly blown backward by the force of the explosion. His ears ring and he feels something warm tickle the side of his face as he stands clumsily, freezing in place, utterly helpless. This wasn't supposed to happen, it's—it's not happening. This can't be happening.

It can't be...his fault, can it?

In the back of his mind comes a soft whisper—he hadn't expected to care; he hadn't expected for it to hurt—_why does it feel nothing like before?_

Waves of heat bend the air illusively as he falls to his knees—shards of rubble digging into his bones; cries of anguish, more tortured and rueful than he has ever heard, drown out his thoughts into a clouded white haze. It's only until he discovers that the pained howls have ceased that he realizes he has screamed himself hoarse.

The smoke sears his eyes as he chokes on acrid air; tears trailing down uncontrollably, melding with the grime and ash smeared all over his skin as he shakily pries the eyepatch off, picking his cracked glasses off the ground numbly.

He vaguely registers, perhaps hours later, that Shima has found him, shaking his shoulders, yelling, slapping him across the face once before shoving a phone into his hands and leaving him there, sagging like a puppet whose strings were finally severed.

The rest of the clean-up teams leave too, and soon, Yukio is left there alone. All he can hear are his own breaths and the sharp crackling of the fire, still clinging voraciously to the debris.

Yukio gets to his feet eventually, letting the phone fall from his hands with a dull crack, and he finds himself rummaging through the ruins of the building, shoving the broken pieces of concrete aside, even before the flames have died. What use is it, if the fire won't burn him at all? His nails chip and his fingers bleed but this pain is transient; it grounds his consciousness. He coughs as he inhales more smoke, searching the scraps for remains, belongings, anything that could quench this burning, irrational hope which refuses to settle in his chest.

He pushes against a stubborn section of concrete, kicking, clawing at it furiously, but it refuses to move. Before he knows what he's doing, he's drawn his gun, emptying an entire clip straight at the crumbling wall. For the fraction of a second, he thinks he hears movement and dread constricts his heart as he digs desperately—almost relishing the agony that tears across his muscles—cutting his palms on shards of glass without care.

He'll do anything, so please, _please_, if Yukio could just _find_ him.

He fumbles through the destroyed building—it's almost frustrating that there's so little left, so little to search— countlessly many times, he has the sections engraved into his mind; he turns back to look through them spontaneously, sometimes one by one, sometimes impulsively out of order. He can't stop; if he doesn't give up his efforts will be rewarded, won't they? What if he gives up...what if Yukio _leaves him _there?

Gradually, he gathers a small pile of things. Pieces of charred clothing, the remaining heels of a pair of shoes, a melted earring, a chunk of a belt buckle, a collection of bloodied glass...but none of them are _his_.

It seems he doesn't deserve closure.

The guilt haunts him; it eats at his flesh, festering in his skin-deep wounds and he lingers there, accompanied only by a few coal tars, seeing the pillar of fire behind his eyelids every time he blinks.

He lies against the broken slabs of concrete, staring up at the depthless blue sky, cursing the world for not perishing along with _him_; cursing himself for admiring how endlessly far away, how white the clouds appear through the cracked, ruined lenses of his glasses.

He hadn't thought that his hatred would mean so little in the face of regret. Yukio hadn't thought...he still loved his brother.

As he lies there, he sleeps fitfully. In his dreams, he keeps searching the debris in the dark, fumbling blindly. He's unintentionally memorized the arrangement of the destroyed building, having traced each angle and jagged edge too many times; maybe if he can't see, he'll find something new...but he can't wake up, and the cuts on his hands sting ruthlessly. How can it still hurt if he's only dreaming?

He watches the sky warm to alluring shades of purple and orange, suddenly finding himself pathetic...so pitiable, such a hypocrite, that he laughs and he clutches his sides as he curls in on himself, breathing shallowly as he cries, wails rightfully alone in the empty aftermath of a massacre _he_ was never supposed to know, to step foot in.

In the end, none of it matters to him anymore. The Illuminati, the Order; he couldn't care less about the rest of it. Not when his paltry, asinine strength means nothing in the face of this bleak nightmare.

Yukio spends the next day watching the sun crawl across the sky, and he knows he's well and truly lost it when he finds himself drifting, dragging his feet forward to the station. What is he doing? Why does it hurt so much, when he has no right to mourn? Why does he want to go home so badly; to see if _he_ might be there...waiting?

If he goes there, can this ache in his heart become so unbearable that it will kill him?

He stands there at the abandoned train station, listening to rain pelt the cracked roof until night falls gently. He doesn't mind remaining here; there is no one waiting for his return.

A distant roar thunders through the tunnel. Yukio raises his weary limbs, staring at the soft, welcoming glow of the blurring windows. He squints at the destination plate, blinded by the glaring, bright headlights. And perhaps, he's been given a chance; a way to end it all. He covers his left eye tightly as he makes his decision; this time, he won't ask for anything else.

Now, he knows he has never seen clearer. As the Phantom Train's lights sway, come closer, he feels relieved at last. If he fails here, he won't need to suffer the disappointment. He will have nothing left to give.

It shows no sign of slowing down—that's fine, he hadn't intended to ride it—wobbling and creaking loudly as it rapidly approaches.

Yukio draws in one last breath, and steps forward.

* * *

He gasps, wheezing as though he was winded and opens his eyes to an enthusiastic mop of black hair, with startlingly familiar blue eyes, hovering above him.

"He woke up! Hey, Yukio, Tou-san, he woke up!"

"Oh? See, Rin, I told you he would."

Rin's face is rounded with childish glee as he beams, almost bouncing with excitement as he pulls _Yukio—_with soft teal eyes and barely hidden curiosity lining his smile—over to the bed.

Blinking uncontrollably, he raises a trembling hand and fumbles for his glasses. The world blurs rapidly and warm tears—he'd thought he couldn't cry anymore at this point—pool at the corners of his eyes. He must not be seeing this right.

Because, _God, _if this is his punishment, the world is far too merciful.

* * *

The cuts on his hands are superficial at most and although painful, they require little attention. Other than severe dehydration, there is nothing keeping him in bed.

Father Fujimoto had ushered Rin and Yukio away, telling them to let him rest with some mild concern lingering in his gaze as pulls a chair to sit beside the bed.

"How are you feeling?" he asks, offering Yukio a tissue box.

Yukio sits up, minding the IV they've set up for him, slouching against the soft pillow as he fails to keep himself from clenching his fingers, digging his nails into the wounds to assure he isn't...dead—isn't dreaming. He swipes at his tears quickly, biting the inside of his cheek as he tries to restore his composure.

"I'm fine," comes out of his mouth compulsively before he can stop it.

Father Fujimoto nods, "What were you doing at the train station so late?"

Yukio falters. Father Fujimoto looks so much younger compared to when Yukio last saw him. It's horribly surreal to see him again. His father's death had scarred him deeply, feeding the contempt he held for Rin—

_You said something, didn't you? If Tou-san could ever be said to have had any weakness, it would have been you. You...Nii-san, were the one who killed Tou-san._

How could he have said that, before?

_Just die, please._

And it _aches_ that he can never apologize, that his brother is truly gone. It's not fair that Yukio survived; that Rin had called Yukio _family_ in his next breath, as he'd held him at gunpoint.

It could have been a coincidence, that Rin happened to be there, at the facility. And now, another coincidence has led him here.

Yukio clenches his fists hard, feeling the cuts sting dimly as he bows his head, watching heavy droplets darken the blanket piled at his waist.

He will use the rest of his life—that he'd selfishly tried to throw away—to finally fulfill his promise.

_In ten years time...your brother will witness something far more frightening. Rather than living in fear of the darkness…_

"I'm Okumura Yukio," he declares, voice coming out shakily, with a slightly dry, rasping tone, "I came from ten years in the future. I'm here to stop myself."

Father Fujimoto's eyes widen behind his glasses, gasping softly as he stares, doubtlessly beginning to notice the similarities.

Yukio shifts his gaze away, looking down at his bandaged hands, "To stop myself from making a mistake." He can't say it aloud yet; doesn't dare say it when he just saw Rin and Yukio moments ago.

"What happened? You are really Yukio," Father Fujimoto whispers, lines of stress creasing his forehead. "How did you come back? Even Mephisto can't— did you use the key?"

Yukio blinks in confusion, "What key?"

"Then," Father Fujimoto frowns, "how did you get here?"

_To become strong, and be able to protect other people—your brother included._

"It was a gamble," Yukio admits, "I'm sure...it's because I didn't have anything left to lose." He's afraid Father Fujimoto will be unnecessarily concerned for his mental health—he has it under control now, he won't throw this chance away.

He won't try to throw his life away again.

This time, he'll make it up to Nii-san.

* * *

AND, some more notes . Sorry, but I just have so much I feel like I need to say, but no one really reads these anyway? So...

Hello!

Thank you for reading! This fic is the continuation to Temporize, so I wonder if you guys might be able to guess what's coming next? :) Anyway, I just have a bit more that I'd like to explain, especially with some parts I was purposely vague on, but didn't want anyone to be confused about.

So, after we see Shima use the black flames a few times, they explain that it burns the inside, but doesn't hurt the body. The bomb I made up is like, a normal bomb, plus the fancy crystals and flames to basically be indiscriminate and like, kill everything. Also, because if the bomb was only composed of the Armumahel crystals and stuff, Yukio would have found a bunch of bodies lying around.

Then, I made up the part about the catalyst for the gates. I don't remember how long Mephisto estimated it would take for the gates to open completely, but I feel like the Illuminati researchers could work a little harder to pick up the pace, especially with Mephisto out of the picture now. I don't know, I feel like the manga is heading to a dark place. Like, how are they even supposed to win?! Which is also why I've written Yukio with absolutely zero motivation in the beginning. Because the world's ending in this fic.

Okay, one more important thing is the Phantom Train. This guy shows up in the Ao no Exorcist movie with Usamaro and it's super cute and just an amazing movie in general! If you haven't watched it, you really should! I really recommend it! I think I cried the first two times I watched it, but it's actually a great ending with so many fluffy feels. Like, one of the best anime movies I've ever seen from the shonen genre. Anyway, so the Phantom Train is kin of Samael (Mephisto) so it travels between Assiah and Gehenna.

Oh, and, just as one last thing, Yukio wasn't thinking straight, so he rushed over to the building before the fire was out. I mean, obviously he wasn't going to wait for the fire to go out, then try to save people, but this is actually very dangerous. Part of the reason why he wheezes when he wakes up is because he has symptoms of smoke inhalation. This isn't always a serious problem, but just be careful to stay close to the ground in a fire because there's more oxygen down there. :D

Again, thanks for reading! Especially since my notes are so long. XD I hope you'll like this! If you don't mind, please leave a comment on how I did! Even criticism is encouraging and it feels really nice to know that people are reading this.

Honestly, I this fic needs a bit more editing (I was told by my wonderful beta that some parts were shallow and cringy but IDK how to fix my crappy writing anymore at this point) but I'll probably come back and fix it up a bit more later, once I've written a few other chapters. So, sorry about the confusing tenses in the middle and the bad writing in general. Let me know if some parts sound weird, okay? ^^

Aww, I'm so sorry for such a long notes section. I feel like this whole thing is like a sandwich but only the filling is good. T.T

I'm really excited to write the next part, and I promise it will be happier. :)

-bluewindfall

PS, I'm on tumblr. If you like my writing, maybe give me a follow? I don't really post relevant stuff...but I'll follow you back! :D (Also, there's like this one writing prompts thing that I really want to do, but none of my followers ever ask me anything or send prompts. T.T )


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